bool数组标记

#include <iostream>
#include <string.h>

using namespace std;

int n,m,a[1000],x,f[1000];

int main(){
	int n;
	
	while(cin >> n){
		memset(f,0,sizeof(f));
		for(int i = 0;i < n;i ++){
			cin >> a[i];
			f[a[i]] ++;
		}
	
		cin >> m;
		while(m --){
			cin >> x;
			if(f[x])cout << "YES" << endl;
			else cout << "NO" << endl;
		}
	}
	return 0;
} 

map标记

#include <iostream>
#include <map>

using namespace std;

int n,m,x;

int main(){
	map<int,int> mymap;
	
	while(cin >> n){
		for(int i = 0;i < n;i ++){
			cin >> x;
			mymap[x] ++;
		}
		cin >> m;
		while(m --){
			cin >> x;
			if(mymap[x])cout << "YES" << endl;
			else cout << "NO" << endl;
		}
	}
	return 0;
}